It is more particularly applicable for decorating voluminous objects by logotypes, signs, letters or distinctive figures which can be painted on the surface of said objects and more particularly for the decoration of aircraft and especially the decoration of the outer surface of an aircraft by logotypes, signs, letters or distinctive figures selected by the air company operating said aircraft.
In the follolwing description, the invention shall be described concerning its application for decorating aircraft, this application not, however, being restrictive.
Generally speaking, the painting of aircraft consists of first of all applying sub-coats of protection paint and of then applying to these sub-coats a "background" paint, generally white. It is on this background paint that the logotypes, signs, figures or distinctive letters are to be applied as selected by the air company operating the aircraft in order to decorate the plane.
In order to protect its brand image, each airline company requires that an aircraft manufacturer provides suitable decoration, especially as regards all the distinctive logotypes and signs painted on the outer surface of the aircraft.
This outer decoration is generally embodied artistically and requires a series of extremely meticulous operations effected subsequent to the difficulties encountered by specialized decorators and painters for picturing in a three-dimensional space the aspect to be acquired by the logotypes, distinctive signs, etc., initially represented in two dimensions on the drawings. In fact, the airline company, the customer of the manufacturer, represents most of the time the desired two-dimensional decoration on a drawing. If a representation of the aircraft and its decoration are supplied to the manufacturer, they may only be approximative and in any event be unable to be used for being directly transferred onto the aircraft, even after being enlarged, due mainly to the fact that the choice of the dimensions and location of this decoration on the aircraft depend on the shape of this aircraft. Generally speaking, a definitive choice of decoration may only be carried out after the embodiment of a first decorative prototype on an aircraft; this prototype is subjected to various retouches which on each occasion require at least a partial rubbing out of the decoration. This process is long and costly, although the descriptive drawings of the decoration represented in two dimensions may be effected by means of CAD (Computer-Assisted Design) and the characteristic dimensions and positions of the decoration are defined by details on these drawings.
The drawings obtained by CAD are supplied to the airline company by the manufacturer or result from a collaboration between the airline company and the manufacturer. The obtaining of CAD drawings does not dispense with the need to embody a prototype decoration of a first aircraft, as well as the retouches mentioned earlier and the corrections of the initial drawings rendered necessary by these retouches. It is only when the airline company considers satisfactory the aspect of the prototype decoration that a definitive drawing can finally be validated.
Once the actual decorative prototype on an aircraft has been validated, a set of pouncing patterns (sheets pierced with marking holes) are noted on this aircraft so as to reproduce an identical decoration on the other aircraft of the airline company in question. Each pouncing pattern is constituted by a flat translucid film on which perforations are embodied and situated on the lines required for defining the decoration. Then marking means are used to position the pouncing pattern on the objects to be decorated. These marking means are references for positioning the pouncing patterns of each aircraft. They need to be positioned precisely with respect to the characteristic contours of the elements of the aircraft, for example the edges of the cabin windows or doors. The pouncing patterns are then filed and reused for the aircraft of a given type of a particular airline company.
The method described above has one major drawback: it is difficult to reproduce on a three-dimensional object a plotting embodied on a two-dimensional drawing. Another drawback results from the fact that the quality of the reading on a pouncing pattern of the validated decoration prototype of an aircraft conditions the quality of reproduction of the decoration on other aircraft.
Another drawback arises from the difficulty of fully plating a flat pouncing pattern on an open-ended support. Finally, the pouncing patterns, which frequently are always numerous and have large dimensions, present problems of archiving and need to be renewed after several usages.
A more recent method is able to automatically cut decoration stencils (sheet cut to the desired shape) intended to be applied to a tridimensional surface, such as the fuselage of an aircraft. The painting of the decoration, especially when a stencil is used, is generally effected with a gun. The cutting method consists of using a CAD processing system and CAD adapted program so as to obtain a tridimensional model representative of the outer surface of an aircraft to be decorated and a bidimensional model of an image of the decoration projected into an intermediate plane; the processing system and program are also able to position the bidimensional model with respect to positioning references concerning the tridimensional model. The method then consists of carrying out projection calculations so as to obtain a tridimensional representation of the decoration correctly positioned on the tridimensional model. The tridimensional representation data of the decoration and the aircraft are recorded. The processing system then controls means for cutting the stencils required for decoration and means for marking positioning references on said stencils.
The method described above also has a number of drawbacks:
Obtaining an acceptable stencil for decorating a first aircraft often results from the cutting of several stencils used for decorating tests on the aircraft, this proving to be expensive and time-consuming. Stencils like pouncing patterns need to be archived and be renewed after several usages, indeed after a single usage if these stencils are self-adhesive.